The present invention relates to a connector for electrically connecting a plurality of printed circuit boards (PCBs) and, more particularly, to a connector for electrically connecting a plurality of mother boards incorporated in, for example, a cross-connect switch device constituting a node of a synchronous network, asynchronous network or ATM (Asynchronous Transfer Mode) transmission network for individually mounting a plurality of PCBs on each of which a number of electronic parts, e.g., LSIs, are packaged.
Generally, a cross-connect switch device for the above application has a plurality of input switch circuit groups, a plurality of output switch circuit groups (with or without an intermediate switch circuit group, depending on the required cross connecting function), and wiring networks interconnecting the input and output switch circuit groups. A number of electronic parts constituting each of the switch circuit groups and including LSIs are mounted on each of a plurality of PCBs which are in turn mounted on a single mother board. The wiring networks are formed on the surface of the mother board and connected to the PCBs.
Assume that the mother board is affixed to the rear wall of a rack, that the PCBs constituting the input switch groups are mounted on a lower portion of the mother board in parallel with the side walls of the rack (i.e., perpendicular to the ground), and that the PCBs constituting the output switch circuit groups are mounted on an upper portion of the mother board in a horizontal position. Then, the wiring networks provided on the mother board and interconnecting the input and output switch circuit groups are implemented by a number of printed circuits extending in the up-and-down direction without crossing one another.
The mother board of such a cross connect switch device is sometimes divided into a lower mother board for mounting the PCBs assigned to the input switch circuit groups (referred to as input PCBs hereinafter), and an upper mother board for mounting the PCBs assigned to the output switch circuit groups (referred to as output PCBs hereinafter). Then, such two mother boards are connected together by a connector.
The above-mentioned connector is usually implemented as a substantially parallelepiped block made of an insulating material. Such a connector has a surface for connecting to the lower mother board on the front thereof and a surface for connecting to the upper mother board on the rear thereof. A plurality of conductive pins are buried in the connector such that their opposite ends protrude from the front and rear of the connector. The ends of the pins protruding from the front of the connector are passed through through holes formed in the lower mother board and then inserted into contact forming holes located at one edge of the input PCBs. The other end of each pin protruding from the rear of the connector is inserted into a hole formed in the upper mother board and then soldered to a printed circuit which is provided on the mother board.
When the mother board with the input PCBs and the mother board with the output PCBs are connected by the conventional connector, the latter mother board has to have the number of layers constituting the laminate printed circuit thereof increased with the increase in the number of wirings between the input and output switch circuit groups. However, since the number of layers available with the laminate printed circuit is limited, the conventional connector is not practicable when the number of wirings between the input and output switch circuit groups is large.
It is therefore an object of the present invention to provide a connector capable of connecting the input PCBs and output PCBs of a cross-connect switch device without increasing the required number of wirings between input and output switch circuit groups.